TNS Classification Report No. 21955 [ 2025TNSCR3531....1P ]

Date Received (UTC): 2025-09-02 19:22:53
Sender: Ismael Perez-Fournon
Group: SGLF

F. Poidevin (IAC and ULL), S. Geier (GRANTECAN and IAC), I. Pérez-Fournon (IAC and ULL), D. Cano-Morales (ULL), N. Elías-Rosa (INAF and ICE/CSIC), D. Aguado (IAC and ULL), and A. López-Oramas (IAC and ULL) report/s a classification of object: SN 2025ndr

Type: SN Ia-CSM
Redshift: 0.182

Remarks: SN Ia-CSM classified with NOT ALFOSC (grism 4). Z = 0.182 from host galaxy emission lines. It was selected for spectroscopic follow-up as a SLSN candidate using the ALeRCE light curve classification and the reports of Sheng et al. (AstroNotes 2025-191 and 2025-218) and Perley et al. (AstroNote 2025-199). Dhawan et al. (AstroNote 2025-226) classified it as a possible bright peculiar/lensed SNIa at z = 0.185. Using SNID (Tonry and Davis 2007) good matches of our NOT ALFOSC spectrum are obtained to templates of SNe Ia-CSM after maximum light (e.g. SN 2005gj at 39 to 52 days post maximum light). The ZTF light curve is available at the LSST/ZTF brokers, e.g.: https://alerce.online/object/ZTF25aatpeel, https://lasair-ztf.lsst.ac.uk/objects/ZTF25aatpeel, https://antares.noirlab.edu/loci/ANT20252n962qnwpllq, https://fink-portal.org/ZTF25aatpeel

The following Classification spectrum was provided:

Obsdate: 2025-08-14 23:45:00
Instrument: ALFOSC
Telescope: Nordic Optical Telescope

Details of the object and its spectra can be viewed here: https://www.wis-tns.org/object/2025ndr